Engine stop and start systems, such as idle reduction control systems, have been recently developed. Such engine stop-and-start systems perform an engine stop-and-restart task. The engine stop-and restart task is designed to automatically stop an internal combustion engine of a vehicle in response to detecting a driver's engine stop operation, such as the operation of a brake pedal. The engine stop and restart task is also designed to restart the internal combustion engine (referred to simply as an engine) in response to detecting a driver's operation to start the vehicle, such as the operation of an accelerator pedal. The engine-stop-and restart task aims at reducing fuel cost, exhaust emission, and the like.
It is desirable to restart the engine as soon as possible in response to the occurrence of an engine restart request in view of improvement of the driver's drivability of the vehicle. Various technologies have been proposed for addressing such a desire.
For example, Japanese Patent Application Publication No. 2005-330813 discloses an engine stop and start system. The engine stop and start system is equipped with a starter including a pinion (pinion gear) and a motor for rotating the pinion, and also equipped with two solenoids that are drivable individually. When energized, the first solenoid causes the pinion to shift to a ring gear coupled to an output shaft of the engine to be engaged therewith. When energized, the second solenoid causes the pinion of the motor to be rotated while the pinion is engaged with the ring gear, thus restarting the engine.